1. Field of the Invention
The invention concerns a screw connection, in particular for plastic members, comprising a screw and an insert member, which is to be non-rotatably fitted into one of the components involved in the connection and which receives the screwthread of the screw in an axial passage.
2. Description of the Related Art
Screw connections of that kind are known, in the form of so-called micro-screw arrangements for small and more specifically thin-walled plastic members. Because these connections are frequently not capable of withstanding the forces which occur when screwing in the co-operating screwthread of self-tapping screws, the state of the art involves using insert members which, in the operation of injection molding of the plastic component, have plastic material injected therearound (referred to as inlays), or which are subsequently embedded hot into the (thermoplastic) plastic member or by means of ultrasound (referred to as inserts). These known insert members comprise brass and are produced in the form of turned components with a female screwthread in the passage and an outer knurling or the like for the purposes of increasing their resistance to rotation in the embedded condition. A metric steel screw is used as the screw. This known screw connection not only requires relatively high manufacturing costs but it is also high in weight, which is undesirable in many situations of use, for example in the case of mobile telephones. Furthermore the necessary tolerances of pre-cut screwthreads reduce the security of the screw connection against coming loose of its own accord, in particular when dynamic loadings are involved; in addition to this, there is also the loss of prestressing force as a result of fluctuating temperatures because of the different coefficients of thermal expansion of the materials involved.